In ski boot design, one of the most important requirements is to rigidly connect the skier's foot to the boot so that movements by the skier's leg are immediately translated to the ski for maximum skiing control.
Currently, most ski boots are constructed from a substantially rigid outer shell formed of plastic and a substantially flexible inner boot received in the outer shell, this inner boot being formed of foamed plastic covered with leather or rubber. This construction, due to the rigidity of the outer shell, has been a vast improvement over the prior all-leather ski boots, which allowed large amounts of relative movement between the foot and the boot. However, a relatively loose fit is still present due to possible movement of the skier's foot relative to the inner boot. This especially occurs in well used boots where the resilience of the foam decreases.
While numerous prior art devices have attempted to rigidly support a skier's foot in a boot, these devices have not been entirely satisfactory and there is a need for improvement. Examples of these prior art devices are disclosed in U.S. Pat. Nos. Des. 153,731 to Rominger; 173,971 to Smith III; and 205,993 to Ali; and U.S. Pat. Nos. 2,660,812 to Henke; 2,935,798 to Piberhofer; 3,327,410 to Park, Sr. et al; 3,522,668 to Fesl; 3,530,594 and 4,030,215 to Vogel; and 4,160,332 to Salomon. In addition, such prior art devices are disclosed in German Pat. Nos. 225,507 and 1,007,668.